1. Field of the Invention
The present invention relates to a novel socket plug, more specifically, to a socket plug that can be easily attached to a lighting fixture, can be manufactured at low cost, and affords suitable accommodation for electrical conductors.
2. Description of the Related Art
As an example of a socket plug that is attached to a lighting fixture by means of rotation, there is provided a straight-type socket plug, which is integrally formed of substantially axially aligned portions, namely, a bulb attachment portion to which the bulb is attached, a lighting fixture attachment portion attached to a lighting fixture, and a rear end portion to which connectors are attached or through which electrical conductors are guided outwards. It is not easy to apply a force to such a socket plug when the socket plug is attached to or detached from the lighting fixture, which causes a problem of deterioration in workability.
To solve the problem, a socket plug "a" shown in FIG. 6 has been proposed. The socket plug "a" is integrally formed of a bulb attachment portion "b", a lighting fixture attachment portion "c" coupled to the rear end of the bulb attachment portion "b", and a connector portion "d" coupled to the rear end of the lighting fixture attachment portion "c". The bulb attachment portion "b" and the lighting fixture attachment portion "c" are axially aligned with each other. The connector portion "d" corresponds to a rear end portion of the socket plug "a". The connector portion is substantially L-shaped in a side view. A laterally protruding portion "e" has a recess portion (not shown) opening to an end face. Electrical conductor terminals are disposed within the recess portion.
Thus, in attaching the aforementioned socket plug "a" to the lighting fixture, a sufficient rotational force can be applied to the socket plug "a" by taking a grip on the substantially L-shaped connector portion "d", especially the laterally protruding portion "e". Accordingly, the socket plug "a" can be easily attached to or detached from the lighting fixture. However, the aforementioned socket plug "a", which is equipped with the L-shaped connector portion "d", is complicated in shape and thus requires high molding costs. Besides, the electrical conductor terminals cannot be disposed within the recess portion without adopting so-called insert molding, which causes a further increase in costs.